Dental chair



2. t e e h* s Du e h S 3 Nm WA 0H HU RL BA .T WN E .D A u 4.a 0 M 0 m No. 521,256` Patented June 12, 14894,.

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3 Sheets-Sheet 3.

DENTAL CHAIR.

(No Model.)

Patented June 12, 1894.

INVENTOR WITNESSES: i

UNITED STATES PATENT OFFICE.

ARTHUR W. BRoWNE, on PRINoEs BAY, NEW YORK, AssIeNoR To THE s. s. WHITE DENTAL MANUFACTURING COMPANY, oE PHILADELPHIA,

PENNSYLVANIA.

SIEGIFIGALION,l forming part of Letters Patent No. 521,256, dated June 12,1894.l

Application ile'd February 6,1894. SerialNo. 499,283. (No modell) To all whom it may concern:

Be it known that I, ARTHUR W. BROWNE, acitizen of the United States, lresiding at Princes Bay, in the county of Richmoudand' ysuitable embodiment of my invention, with the chair body omitted, Figure l is a view in side elevation. Fig. 2 is a view in rear elevation. various parts omitted, and partly in section on the line 3 of Fig. 1.l Fig. 4 is a detail iew, partly in front elevation, and partly in section on the line 4 of Fig. 3. Fig. 5 is a view partly in front elevation and partly in section on the line 5 of Fig. 3. Fig. 6 is a plan view of the upper arms of the supplementary parallel arms. Fig. 7 is a plan view of the lower arm of the main parallel arms, and also showing partly in section a portion of the link or tension rod connecting the supplementary parallel arms with the turning support. Fig. 8 is .a plan'view of said tension rod. Fig. 9 is a plan View of a modification. Figs. 10 and 1l are side elevations showing portions of the parallel arms with modifications of the means whereby the supplementary arms arel caused tol rock about their jointed connection with the main arms.

Arecessed or hollow base Ais provided with an internal annular ledge or shoulder a constituting a seat upon which is supported a circular plateor disk B which is adapted to turn horizontally and constitutes in connection with two standards B Bf, which are rigid therewith, a turning support for vertically 'adj ustable mechanism which carries the chair body. A ring A' screwed to the base and overlapping the disk B of the turning support serves to hold lthis disk down to its seat Fig. 3 is a View partly in plan, withv l`in the base. Any suitable means permitting of the adjustment of the turning support while serving to lock it against movement after adjustment may be employed.

The vertically adjustable mechanism for raising and lowering the chair body is as follows: A set of parallel arms, in this instance two such arms C'C (hereinafter termed the main parallel arms) are jointed at their inner or rear ends to and between the standards of the turning support by means of pivoting rods b b passing through bearings of the arms, and` .through the standards to which they are t'astened. The lower arm C of the main parallel arms C C terminates at its rear or inner end in a downwardly projecting curved extension C2 rigid therewith and constitutinga lever for a pur-pose in turn to be explained., Atftheir front or outer ends the main parallel arms have connection with each other by way of links D D to the upper and lower ends 'of which the arms are jointed by pivots c c c c'. A set of supplementary parallel arms shown as consisting of two pairs of such arms E E 'and F F have jointed connection with the main parallel arms by means of the links D D and the pivots c c c c' at their front ends, while at their rear ends these supplementary arms E E F F are pivoted to a chair body carrier G at e. e and f f. At their front ends the supplementary arms E F yterminate Vin downwardly projecting extensions d d curved or converging toward each other and connected at their front extremities to constitute an actuating lever. A link or tension rod Il is jointed at oneend to this actuating lever at h, and at its other end to the standards B B of the turning support at h h', this link rod being forked at its inner or rear end so as to embrace the standards. For this link coupling H a chain or equivalent jointed connection may be substituted'. A suitable chair .body (not shown) is to be attached in well known way to the upper end of the carrier G. A reservoir I for oil or otherliquid, and a horizontal cylinder I are carried by the disk B of the turning support, with which they are rigid. A piston J adapted to be moved horizontally in the cylinder I is connected by the connecting rod J with the extension or actu- IOO ating lever Czof the set of main parallel arms, the connecting rod being pivoted at its opposite ends to the piston and said actuating lever. The liquid reservoir is adapted to communicate with the cy'linderin rea r of the piston by a liquid way or passage K at the side ofthe cylinder and provided at or near its opposite extremities with springactuated valves 7c 7c'. The valve la when opened against the pressure of its spring admits liquid to the passage K, and when the valve k is opened against the pressure ot its spring liquid is allowed to pass from this passage to the cylinder behind the piston. These valves are hereinafter termed the inlet valves. A liquid way or passage L at the side of the cylinder opposite that at which the passage K is located is provided with a valve Z (hereinaft-er called the outlet valve) normally held closed by a spring. Vhen this valve is opened liquid is allowed to pass slowly from behind the piston to the reservoir by the passage L. A foot-actuated lever M pivoted over the horizontal cylinder engagesa rod or stem l' of the outlet valve Z and serves to trip the valve when the outer end of the lever is depressed. An elevating lever N pivoted at n Y to one of the standards of the turning support, is normally maintained in its elevated or inoperative position by a spring O. This leveris coupled by a connecting rod or link p to a pump piston P working in its cylinder Q at the side of the cylinder I. The liquid passage K` is intersected by and communicates with this pump cylinder. The reservoir I has a slot t' in its top through which the actuating lever C2 projects for engagement with the connecting rodJ'. A

From the above description it will be seen that when the elevating lever is actuated to work the pump piston, liquid from the reservoir will be forced into the cylinder behind its piston, thus forcing forward the cylinder piston and by its connecting rod actuating the lever C2 of the set of main parallel arms to rock upward their outer ends. The supplementary parallel arms are at the same time elevated with the outer ends of the main parallel arms and are also caused to rock about their pivotal connection therewith by means .of the jointed coupling connection between the turning support and the actuating lever of the set of supplementary parallel arms. ln this way4 the chair body carrier may be quickly elevated to any desired extent. To gradually lower the chair body carrier which is maintained at all times in an upright position the outlet valve is tripped to permit of escape of the liquid from the cylinder behind its piston, and thus allow this piston to be moved inward to the extent desired by the weight of the chair body and its elevating mechanism.

It will be seen that by the employment ot the horizontal reservoir, cylinder, and piston,

the elevating mechanism may be mounted upon its support low down or near the door upon which the support rests and yet admit of a desirable wide range of vertical adjustment of the chair body.

My improvements may be modified in various ways while still retaining novel features of my invention. When a range of Vertical movement less than that which may be iml parted by `the employment of the supplementary parallel arms in addition to the main parallel arms will answer, the set of parallel arms which are jointed directly to the support may be employed without the supplementary arms, and the chair body carrier be jointed tothe outer ends of the set of arms which are jointed to the support and be maintained at all times in an upright position, as will be understood by reference to United States Letters Patent No. 478,672, dated July 12, 1892; and this set of arms instead ot consisting of two members may consist of four members, two in place of each arm C C' as will readily be understood; while instead of the-upper arms E F of the set of supplementary parallel arms being made in two separate parts they may be in one piece as shown by Fig. 9. Although itis preferable tohave the support for the parallel arms mounted upon the base so as to turn horizontally, the turning movement of this support might be dispensed with and a'rigid connection made between it and its carrying base, in which event the chair body could be mounted to turn about the upper end of its carrier in suitable well known way. Instead .of the supplementary parallel arms being provided with the actuating lever and controlling link H, other equivalent means for causing them to rock about their jointed connection with the main parallel arms may be provided, such, for instance, as shown by Fig. 10, in which two gear segments R S meshing with each other are rigidly attached to or formed with the outer ends of the arms E F, and C', respectively.

In Fig. 1l the actuating lever of the supplementary parallel arms is made shorter than elsewhere shown, and the link I-I connects this actuating lever with the lower one (C of the main parallel arms instead of with the support.

I claim as my invention- 1. The combination, in a dental chair, of a set of parallel arms provided with the actuating lever rigid with one of said arms, the support to which said arms are j ointedj one above the other, the horizontal cylinder, its piston, the connecting rod jointed to said actuating lever and piston, the chair-body carrier supported by connection with said parallel arms, and means by which said carrier is maintained at all times in an upright position, substantially as set forth.

2. The combination, in a dental chair, of the main parallel arms linked togetherat their outer ends, the support to which they are ICO jointed, means for actuating said arms,I the supplementary parallel arms jointed to the linked ends of the main parallel arms, means by which the supplementary parallel arms are caused to rock about theirv jointed connection with the main parallelarms upon actuation of these mainarms, and the chair-body carrier jointed to the supplementary parallel arms and maintained at all times in an upright p0- sition, substantially as set forth. Y

the main parallel arms linked together aft their outer ends, the support to which they are jointed, means for actuating these arms, the supplementary parallel arms having jointed connection with the linked ends of the main parallel arms and provided with the actuating lever, the coupling link 'making jointed connection between said'actuating lever and supp0rt,'and the chair body carrier jointed to said supplementary arms and maintained at all times in an upright position, substantially as set forth.

4. The combination, in a dental chair, of the base, the horizontally turning support carriedthereby, a set of parallel arms jointed to said support and one of which is provided with the actuating lever rigid with it, the horizontal cylinder, its piston, means for actuat- -ing the piston, the connecting rod jointed to said actuating lever and piston, thechair- 3. The combination, in a dental chair, of,

body carriery supported by connection with said parallel arms, and means by`which said carrier is maintained at all times in an uplright position. Y

In testimony whereot` -I- aix my signature in presence of two witnesses.

ARTHUR W. 4iaownn Witnesses:

E. T. STARR,

EDw.' F. SIMPSON, Jr. 

